Drawing apparatus



Dec. 16, 1969 F. Fo'l'sTER 3,483,622

DRAWING APPARATUS Filed Jan. 12, 1968 4 Sheets-Sheet 1 IN V EN TOR.

Pkg 202m Fohser Dec. 16, 1969 F. FORSTER 3,483,622

DRAWING APPARATUS Filed Jan. 12, 1968 4 Sheets-Sheet 3 o m 'r- 8 :5

IN V EN TOR.

Dec. 16, 1969 F. FORSTER DRAWING APPARATUS 4 Sheets-Sheet 4 Filed Jan. 12, 1968 INVENTOR BY hslel- I QJMDQ.

United States Patent 3,483,622 DRAWING APPARATUS Fridolin Forster, 220 Randenstrasse, Schaifhansen, Switzerland Filed Jan. 12, 1968, Ser. No. 697,468 Claims priority, application Switzerland, Jan. 16, 1967, 573/67, Patent 447,627 int. (11. B431 13/10, 13/00 US. Cl. 33-23 9 Claims ABSTRACT OF THE DISCLOSURE Drawing apparatus particularly for the production of stereoscopic images in which a drawing board has a drawing mechanism including drawing pencils and the drawing board has a pliable support with two rollers and a plate to guide the support. The drawing board is also provided with supports for the drawing sheet together with a guide rail to guide the supports.

The invention relates to a drawing apparatus, especially for the production of pairs of stereoscopic images, with a drawing board and a drawing mechanism which has a tracing point and two drawing pencils, which are guided in parallel and which will record two curves which are congruent in relation to one another, if and when a curve given in a pattern is traced with the tracing point. If one wants to draw stereoscopic pictures of this type with a known apparatus, then it will be necessary, after redrawing the curve of a pattern, to change the distance between the two drawing pencils before the next curve is redrawn.

This invention avoids the disadvantage referred to by the fact that the drawing board has a first pliable, endless, foil-shaped support guided by two rollers and a plate for a first drawing sheet which is to be attached to said support, on which the first drawing pencil records, and in that a second foil-shaped but stitfer support has been arranged glideably on said first support for a second sheet which is to be attached to said second support and on which the second drawing pencil records. Thus the second support has been attached to a slide which is guided along a guide rail inclined in relation to the direction of movement of the first support by an angle {3 and which is coupled with the first support, so that in the case of movement of said first support it will be shifted along the guide rail.

A preferred construction of the apparatus has for an object the feature that the rollers of the drawing board have been inclined by an angle a in relation to the base rail, to which the board is attached and in relation to which the drawing pencils are guided in parallel, said angle being half as large and directed in an opposite direction as the above mentioned angle [3, which is formed by the guide rail with the direction of movement of the first suppor Furthermore, it will be particularly to the point if the drawing mechanism is attached to a guide rail which is slideable on the base rail and there along, and which is developed in such a manner that upon redrawing, it causes an affinitive transformation of the curve presented on the pattern.

Heretofore, a single drawing pencil has been used and, furthermore, although the drawing board has the above mentioned rollers and the first foil-shaped, endless and pliable support, still it does not have the second support serving for the attachment of a second drawing sheet.

Further objects will be apparent from the following description when considered in connection with the accompanying drawings in which:

FIG. 1 is a diagrammatic top view of a drawing mechanism and a drawing board;

FIG. 2 is a sectional view taken on line 11-11 of FIG. 1 in the direction of the arrows and on a larger scale;

FIG. 3 is a top plan view of the drawing board and a number of parts mounted thereon;

FIG. 4 is a sectional view taken on line IV-IV of FIG. 3 in the direction of the arrows;

FIG. 5 is a schematic top view of a part of the drawing mechanism provided with two adjustable knobs;

FIG. 6 is a sectional view taken on line VI-VI of FIG. 5 in the direction of the arrows, and;

FIGS. 7, 8, 9 and 10 are each diagrammatic views as an explanation of a simple use of the apparatus by way of example.

The drawing apparatus presented shows, according to FIG. 1, a drawing board 1 and a guide rail 2, which have been attached to a base rail 3, FIGS. 2 and 3, in a manner which will be explained in more detail. The guide rail 2 serves for the guidance of a drawing mechanism 4, which has three carriages 5, 6 and 7 and which can slide along the guide rail 2. At point 8, one end of a first guide rod 9 has been articulated to carriage 6, which at its other end, at 10, has been articulated to a second guide rod 11. A third guide rod 13 is articulated to carriage 7, at 12, which has been articulated at its other end at 14, to a fourth guide rod 15. The second and the fourth guide rods 11 and 15 are connected articulately at point 16. The guide rod 15 carries a tracing point 17 and is supported against the table by a traveling roller 19 which is swivelable around a vertical axis 18, the drawing apparatus resting on said table.

The carriage 5 is connected securely with the carriage 7 by a distancing rail 20, so that these two carriages have a constant distance one from the other, while the carriage 6 can be shifted with regard to the rail 20. At point 21, an end of a fifth rod 22 has been articulated to carriage 5, whose other end has been articulated to a sixth guide rod 24 at point 23, which guide rod 24 has been articulately connected with the third guide rod 13 at point 25. The first guide rod 9 and the third guide rod 13 cross each other and have been articulately connected one with the other at their point of crossing designated by 26. One end of the sixth guide rod 24, projecting beyond the articulation point 23, has been supported by the drawing board 1 by a traveling roller 28, which can be swiveled around a perpendicular axis 27. Furthermore, two drawing pencils 29 and 30 are mounted on the sixth guide rod 24, in a manner to be explained in more detail.

According to FIG. 2, the guide rail 2 has a T-shaped profile and two equally long grooves 31 which are V-shaped and which are located below, in alignment with one another, and with which the conically pointed ends 32 of two perpendicular pegs 33 mesh, which have been attached to the base rail 3. The two pegs 33 are located, for example, at the points below the guide rail 2 which have been designated in FIG. 1 by 33, but the guide rail 2 can be shifted in relation to the base rail 3 by an amount corresponding to the length of the two grooves 31. Beside that, the grooves 31 with the ends 32 of the pegs define a swiveling axis around which the guide rail 2 swings because of the weight of the drawing mechanism 4 attached thereto, to such a point as permitted by the traveling rollers 19 or 28, supported by the table or the drawing board 1. The rollers are adjusted in such a manner that the mechanism 4 lies parallel with the table, that is normally in a horizontal position.

The carriage 6 has a chassis plate 34 on which are mounted two pairs of rifiled or grooved rollers 35 having perpendicular axes, of which only one pair is visible in the drawing, whereby these rollers are guided along the edges 36 of the flanges of the T-profile guide rail 2.

A bearing 36' with a perpendicular axis and attached on the plate 34, serves for the mounting of a swiveling bolt 37, to which one end of the first guide bar 9 has been screw attached as a result of which the joint 8 is realized. The oariage 5 and 7 are developed in a similar manner.

Apart from the fact that the sixth guide bar carries two drawing pencils 29 and 30, instead of only one drawing pencil 29 and that, furthermore, the drawing board 1 is inclined only by a small angle in relation to the guide rail 2 and thus also in relation to the base rail 3, instead of being parallel with these, the apparatus that has been described so far corresponds entirely to the known apparatus. It will therefore be sufiicient to state here that if one traces the geometric configuration of a contour with the tracing point 17, the drawing pencil 29 will record the same figure with afiinitive transformation on a paper which lies on the drawing board, thus, for example, it will record an elipse instead of a circle. A shifting direction of the tracing point 17 parallel to the guide rail 2 will cause, an equally large shifting a of the drawing pencil 29, while a shifting direction 12 of the tracing point 17 perpendicular in relation to the guide rail 2, will have as a consequence only a proportional, for example, half as large a shifting b/2 of the drawing pencil 29, whereby the proportionality factor depends on the adjustable position of the tracing joint 17 along the guide bar 15.

Since the guide rod 24 is guided in parallel with the distancing rail 20 by the guide rods 22 and 13, the drawing pencil 30 will execute exactly the same movement as the drawing pencil 29. If one makes both drawing pencils 29 and 30 act upon the same sheet of paper, then one will obtain nothing else but two congruent drawings. But by using the two drawing pencils 29 and 30 for drawing on two different sheets which are moved in relation to one another in a manner explained subsequently in more detail, one will succeed to create a pair of stereoscopic images, as for example in drawing simultaneously two pictures on the basis of a topographic map provided with altitude curves serving as a pattern, which upon viewing in a stereoscope will result in a spatial view of the terrain shown, just as the view of a bodily relief of this terrain.

According to FIGS. 3 and 4, the drawing board has a rectangular wooden plate 39 attached at two strips 38 of the frame. Two rolers 40 mounted at the ends of the strips 38 are mounted along the longitudinal sides of the plate 39 and each of these strips are equipped with a handle or knurled knot 41. An endless cloth 42, for example an oilcloth, is stretched across the rollers 40 and the plate 39, which can thus be shifted either in the direction of the arrow 43 or in the opposite direction by turning the handle 41. A drawing paper, not shown in FIGS.

3 and 4, can be attached on the cloth 42, preferably by means of transparent adhesive tapes which are secured thereon at its edge and on the cloth 42.

On the longitudinal side of the drawing board 1, adjoining the base rail 3, another strip 44 of the frame has been provided above the pertinent roller 40, whose ends have been attached to the strips 38. A small plate 44' has been attached, for example screwed on, in the middle of the strip 44, which had been provided with a hole 45 having a thread, into which a screw 46, having a milled head, is screwed in; the screws 46 serve for the attachment of one end of a guide rail 47 to the strip 44. The other end of the guide rail 47 has been screwed on by means of a screw 48, with a milled head, to one end of a fishplate 49. The fishplate 49 has a hole 56 near its other end, with which a peg 51 meshes and projecting provided with which there meshes a peg 55, shown in the drawing by the same circle, which has been attached to the base rail 3. A second peg 56, provided in the base rail 3, engages with a hole 57, likewise shown by the same circle, and which has been provided in a fishplate 58, which has been attached at that end of the strip 38, for example screwed on, which has been provided at its other end with peg 51.

The holes 45, 50 and 57 have beenplacedin thesmall plate 44' or in the fishplates 49 and-58 in such a manner that the angle a, which is formed by the rollers 49 with the base rail 3, will be exactly half as large as the angle a, which is formed by the guide rail 44 with the direction of movement 43 of the cloth 42.

A small plate 42'. has been attached, preferably stuck on, to the cloth, from which a driving peg 59 projects upward, which engages with a slot 60, which has been provided in a cross piece 61 of a slide 62 which can be shifted along the guide rail 44;On the slide 62 and laterally on the guide rail 44, two guide heads 63 have been attached. Each guide head 63 has been provided With a permanent magnet 64 which strives to hold the head 63 firmly against the guide rail 44 consisting of iron. As a result of that, a roller 65, mounted rotatably on the head 63, will come into contact with the rail 44, so that the slide 62 will, to be sure, be held against the rail 44 but still is slideable along said rail. The edge of a fairly stiff foil 66, preferably consisting of plastic, and lying to the right in FIG. 3, has been attached to the slide 62, said foil lying on the cloth 42, but in the case of a relative movement between the slide and the cloth it will guide without being deformed on said cloth in the direction of the arrow 67 or in an opposite direction.

It is apparent, that the directions 43 and 67 of the movement of the cloth 42 and of the sliding foil 66 both enclose together with the direction, which is perpendicular in relation to the base rail 3, the angle of the same magnitude but with a diiferent sense, as indicated by the two rotational arrows 68.

FIGS. 5 and 6 illustrate, in principle, how the drawing pencils 29 and 30 are mounted on the guide rod 24 without at the same time showing any constructional details. The drawing pencil 29 is part of a drawing head 69 which has a mounting block 70 attached, for example screwed on, to the guide rod 24. The block 70 has a perpendicular bore 71 in which the drawing pencil 29 is guided, for example by means of wellknown ball bearings, which have been provided in so-called Thompson bushings. The upper end of the drawing pencil 29'has been attached to the pressure plate 72 which is supported by the piston rod 73 of a piston 74. The piston 74 is arranged in a cylinder space 75, which has been hollowed out in the block 70, with the wall of which it is connected in, an airtight manner by means of a folding membrane 76. A bore 78, to which a hose 79has been attached, which starts out from a side arm of a T-iron or connection 80, goes into a part of the cylinder space 75 located beneath the piston 74. A second hoser79 starts out from the other side arm of the T-iron 80 attached to the guide rod 24, which leads to a second drawing head 69, mounted on the guide rod 24, which is provided with the drawing pencil 30. A hose 81 is attached to the middle section of the T-iron 80, which is attached to the guide rod 22 at 83 and with a loop 82, taking into consideration the relative movements of the guide rods 22 and 24 and which finally lead to a small rubber ball 83' which lies on the floor to function as a pedal.

If one does not press on the ball 83, then thepoint of the drawing pencil 29 rests, under the influence of its own weight and of that of the pressure plate 72, on a first paper 84, which had been secured onto the cloth 42. Likewise the point of the drawing pencil 30 rests on a second paper 85, FIG. 7d, which has been secured onto the sliding foil 66. If one presses against the ball 83' with ones foot, then the pertinent piston 74 is shifted upward by the pressure created in the lower part of the cylinder space 75,, so that the drawing pencils 29 and 30 are lifted off from the papers 84 and 85 by the piston rod 73 and the pressure plate 72. The person using the apparatus therefore does not use his hands for lifting oif the two drawing pencils 29 and 30, so that he can comfortably operate a handle 41 for the shift of the cloth with one hand and he can guide with the other hand the tracing point to follow a curve, for example of a straight line of a falling body.

It is clear that one can use as a drawing pencil a lead pencil, a ball point pen, a fountain pen with India ink or similar device.

Since in the drawing of topographic maps it is important to shift the cloth 42 each time by precisely the same amounts corresponding to the difference between the altitude curves, the drawing board 1 has been equipped with a click-stop arrangement 86, which causes, each time after a predetermined feed of the cloth 42 which can be adjusted to various values, a very perceptible increase of the force required for a continued turning of the handle 41, so that each time, after the redrawing of an altitude curve which is traced with the tracing point 17, one can, without difiiculty, adjust the required feed for the redrawing of the subsequent altitude curve.

For an explanation of the method of operation of the apparatus described, its application according to FIGS. 7a to 7d for the drawing of a pair of stereoscopic images which represent a cube will be explained.

FIG. 7 shows a cross section 87 of a cube, serving as a pattern, Whose length of edges has been designated by in. On a straight line of reference, designated by r, which is placed in parallel to the base rail 3, a reference point R has been marked. FIG. 8 shows the straight line of reference r which has been recorded by the drawing pencil 29, whenever the tracing point 17 is guided along the straight line 2', whereby the point R corresponds to the reference point R. In order to facilitate the understanding, FIG. 8 shows how the presentation is accomplished, whenever the angle a=0. When the tracing point 17 is guided to follow the square 87, then the drawing pencil 29, assuming a 50% foreshortening in a direction perpendicular to the base rail, will draw a parallelogram 87' corresponding to the upper surface of the cube. If the cloth 42 is shifted perpendicularly in the direction of the base rail 3, while the tracing point 17 is, for example, at the corner point, which corresponds to the perpendicular edge 88, then the drawing pencil 29 will draw the straight line 88'. The assumed 5 0% foreshortening corresponds to an inclination of 60 degrees of the upper surface of the cube in relation to the plane of the drawing of FIG. 8, while cos 6O degrees=0.5. Therefore, the edge 88 has an inclination of 30 degrees in relation to the plane of the drawing of FIG. 71;, so that in the case of parallel projection the length of its projection 88 equals m. cos 30 degrees=0.866 m. If one traces once more with the tracing point 17 along the square 87 after shifting the cloth 42 by 0.707 m., then a second parallelogram 872: is drawn, which represents the lower surface of the cube. The other perpendicular edges are obtained again by shifting the cloth 42 while the tracing point 17 stands still. In a simple manner one can draw the visible edges of the cube with heavier lines by placing a small weight on the pressure plate 72 of the drawing pencil 29.

In FIG. 10, the plane of the paper 84, stuck onto the cloth 42, has been assumed as the drawing plane and in FIG. 7d, the plane of the paper 85, stuck onto the sliding foil 66. The images drawn by the drawing pencils 29 and 31 differ from the image according to FIG. 8 by the fact that the perpendicular edges of the cube, for example 88, are now inclined by the angle a in relation to the perpendicular line on the line of reference 1', or 1- but on opposite sides of the perpendicular line. One can select the same rate of feed of the cloth as in the case of 6 FIG. 8, so that the projections 88, or 88 of the perpendicular edge 88 of the cube will again have the length of 0.866 111. One can also select any other desired feed.

The selection of the rate of feed of the cloth is not made as a rule in such a manner, even in the case of the practical application of the basic instruments, that a pure parallel projection will result, rather, in the case of redrawing of topographic maps into so-called block images, the differences in altitude between succeeding altitude curves are represented in a greatly enlarged manner.

If one views the images of FIGS. 9 and 10 in a stereoscope, whereby one must first of all bring the lines of reference lines r and r and the points of reference R and R to cover each other, then one will obtain in a known manner a three-dimensional view of the cube. The advantage of the apparatus described lies in the fact that one can draw both images simultaneously in a very simple manner. The apparatus described is suitable in an excellent rnanner for the recording of stereoscopic images from geometric bodies, landscapes, buildings, atomic grid models, etc.

In order to increase the stereoscopic effect or in order to decrease it, the angle a can be made larger or smaller, while maintaining the ration 5:2a. Besides the hole 57 of the fishplate 58, two holes 57 and 57 have been provided for this purpose and besides the hole 50 of the fishplate 49 and two screw holes 45 and 45 besides the screw hole 45 in the small plate 44. If one places the pegs 51 and 56 into the holes 50 and 57 or 50 and 57 and if one screws the screw 46 into the screw holes 45 and 45 then one will obtain a larger or a smaller angle a. In practice, the angle on must not surpass a value of about 6 degrees, since, otherwise, the eye cannot be properly accommodated.

One can remove the fishplates 49 and 58 as well as the strip 44, the guide rail 47, the slide 62 together with the sliding foil 66 and the small plate 44', in order to use the apparatus as a basic instrument for the drawing of perspective views, whereby a hole 54 provided at the upper end of the right-hand strip 38, is placed on the peg 56 of the base rail 3. Vice versa, the basic device can be changed into an apparatus drawing stereoscopic images by the addition of the above mentioned parts, as well as the second drawing head 69 with the second drawing pencil 30 and the T-iron or joint 80.

It may still be mentioned that the drawing board 1, which has been described, can also be used with some other mechanism 4 than the one shown, for example, with the drawing mechanism shown initially with which, if one follows the curve with a tracing point, one will be able to draw with the drawing pencils two curves which are congruent in relation to one another, however without aflinitive transformation. In that case one will obtain the advantage that in the transition from one altitude curve to the next one, one will not have to change the distance of the drawing pencils from each other.

I claim:

1. Drawing apparatus, especially for the production of stereoscopic images, comprising a drawing board, a drawing mechanism which has a tracing point, two drawing pencils mounted on the mechanism and guided parallel to draw two curves which are congruent in relation to one another when one follows a pattern as to any given curve with the tracing point, the drawing board having a first foil-shaped and endless pliable support, two rollers and a plate for guiding the support, a first sheet for the drawing to be attached on said support on which a first drawing pencil draws, a second foil-shaped and rigid support arranged to slide on said first support for a second drawing sheet to be attached to said second support a slide on which the second-mentioned support is attached, a guide rail to guide the second-mentioned support and which is inclined at an angle in relation to the direction of movement of the first-mentioned support, and means to couple the second-mentioned support with the firstmentioned support so that it will be shifted along the guide rail in the event of movement thereof.

2. Drawing apparatus according to claim 1, in which a base rail is provided, the rollers of the drawing board being inclined at an angle relative to the base rail to which the board has been attached and in relation to which the drawing pencils are guided in parallel, said angle being half as large and oppositely directed in relation to an angle which is formed by the guide rail and the direction of movement of the first support.

3. Drawing apparatus according to claim 1 in which a plate is provided secured to the first su port from which a driver pin projects upwardly, which engages with a slot in a cross piece of the slide.

4. Drawing apparatus according to claim 1, in which a slide is provided and two guide heads are provided attached on the slide, each of the heads having a permanent magnet and a roller whereby the magnet will tend to hold the heads on the guide rail and consisting of ferromagnetic material so that the roller is pressed against the rail.

5. Drawing apparatus according to claim 1, which in the angle between the guide rail and the direction of movement of the first support is adjustable to varying values.

6. Drawing apparatus according to claim 1, in which a fish plate is provided with one end of the guide rail attached by means of the fishplate which has different holes of attachment therein to a part of a frame of the drawing board, and the guide rail being attached on another part of the frame by means of a small plate which has various holes of attachment therein to a part of a frame of the drawing board and the guide rail being attached on another part of the frame by means of a small plate which has various holes of attachment therein the drawing board has been attached to the base rail by means of fishplate. having various holes of attachment therein whereby the holes of attachment of the two fishplates and of the small plate being arranged so that they have been assigned to one another in such a manner that in the case of the use of an assigned hole of attachment, the angle will always be twice as large as an angle.

7. Drawing apparatus according to claim 1, in which means are provided to attach the drawing mechanism on a guide rail, which is slideable on and along the base rail, and which has been developed so that in the case of redrawing, an affinitive transformation of the curve shown on a pattern will be brought about.

8. Drawing apparatus according to claim 1, in which a pedal is provided attached to operate the drawing pencils so that they can be lifted pneumatically from the drawing sheets by means of the pedal.

9. Drawing apparatus according to claim 1, in which a click stop device is provided so that at least one of the rollers provided with a handle is coupled with the clickstop device which, when turning the handle either forward or backward, and each time after equal and successive feed steps of the first support, will otter an increased rotary resistance.

References Cited UNITED STATES PATENTS 2,714,253 8/ 1955 Stone. 2,835,974 5/ 1958 Wilkinson et al. 3,295,210 1/1967 Kelsey.

HARRY N. HAROIAN, Primary Examiner U.S. Cl. X.R. 33-18 

